如何将属性访问器作为函数参数传递？

Question

我想传递一个属性acessor或object literal＆＃39; key＆＃39;作为函数中的参数，所以我可以在for循环中使用点符号。

例如：

＆＃13;

＆＃13;

let myArray = [
{
apples: 4,
bananas: 1,
},
{
apples: 10,
bananas: 2,
},
{
apples: 4,
bananas: 3,
},
]

Array.prototype.count = function(objProperty, testValue) {
  var count = 0;
  for (var i = 0; i < this.length; ++i) {
    if (this[i].objProperty === testValue) {
      count++;
    }
  }
  return count
}

console.log(myArray.count('apples', 4)) // expect: 2
console.log(myArray.count('apples', 10)) // expect: 1

＆＃13;

＆＃13;

＆＃13;

Answer 1

您可以访问对象的属性，例如Object.property或Objects[property] (in case, property is a string datatype)

＆＃13;

＆＃13;

let myArray = [
{
apples: 4,
bananas: 1,
},
{
apples: 10,
bananas: 2,
},
{
apples: 4,
bananas: 3,
},
]

Array.prototype.count = function(arrayProperty, testValue) {
  var count = 0;
  for (var i = 0; i < this.length; ++i) {
    if (this[i][arrayProperty] === testValue) {
      count++;
    }
  }
  return count
}

console.log(myArray.count('apples', 4)) // expect: 2
console.log(myArray.count('apples', 10)) // expect: 1

＆＃13;

＆＃13;

＆＃13;